diff --git a/drivers/char/synclink.c b/drivers/char/synclink.c
index afded3a..813552f 100644
--- a/drivers/char/synclink.c
+++ b/drivers/char/synclink.c
@@ -81,6 +81,7 @@
 #include <linux/mm.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/delay.h>
 #include <linux/netdevice.h>
 #include <linux/vmalloc.h>